---

Management of Refractory Anaphylactic Shock

Definition

---

Step 1: Recognize and Secure Basics First

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Step 2: Escalate Epinephrine - IV Route

IV Epinephrine Infusion (PREFERRED over IV bolus)

• Start at 0.1-0.5 mcg/kg/min IV infusion; titrate to response
• Infusion is more effective than IV bolus and results in lower total dose requirement with a better safety profile
• Use a dedicated line with infusion pump and anti-reflux valve when possible
• Continuous monitoring required: vital signs, 12-lead ECG, mental status

IV Epinephrine Bolus (peri-arrest only)

• 1 mcg/kg IV - reserved for peri-arrest or cardiac arrest scenarios
• Higher risk of dysrhythmias; not routine

---

Step 3: Aggressive Fluid Resuscitation

• 20-30 mL/kg of crystalloid IV as rapidly as possible, preferably via large-bore cannula
• Balanced crystalloids preferred over 0.9% saline (to avoid hyperchloremic metabolic acidosis and renal vasoconstriction)
• Avoid colloids as first-line (concerns about renal failure and haemostasis disorders)
• Reassess after each bolus; repeat as needed for hemodynamic response
• Avoid high infusion rates for >2 hours (fluid overload risk)

---

Step 4: Second-Line Vasopressors

No single vasopressor has demonstrated superiority over another. Clinicians should use the agent they are most comfortable with, titrated to clinical response. Echocardiography should be considered to exclude myocardial dysfunction requiring a different treatment strategy.

---

Step 5: Glucagon - For Beta-Blocker Users

• Glucagon 1-2 mg IV (or 20-30 mcg/kg in children), repeat every 5 minutes until hypotension resolves, then infusion at 5-15 mcg/min
• Glucagon bypasses β-receptor blockade by stimulating adenyl cyclase directly, increasing cAMP and improving cardiac output
• Side effects: nausea, vomiting, hypokalemia, hyperglycemia, dizziness (aspiration risk in semi-conscious patients)

---

Step 6: Bronchospasm Refractory to Epinephrine

IV aminophylline is NOT recommended. Leukotriene receptor antagonists are ineffective for acute anaphylaxis.

---

Step 7: Corticosteroids

• Hydrocortisone 200-400 mg IV or methylprednisolone 1-2 mg/kg IV
• Do not rely on these for acute hemodynamic instability - they have delayed onset (hours)
• Primary role: prevent biphasic/protracted reactions (occurring 12-24 hours later), and attenuate late-phase response
• In IgE-mediated reactions: hydrocortisone 0.25-1g IV; in complement-mediated reactions (e.g., protamine): methylprednisolone 1-2g (30-35 mg/kg) IV

---

Step 8: Rescue / Last-Resort Therapies

Methylene Blue

• 1-2 mg/kg IV over 20 minutes
• Mechanism: inhibits nitric oxide synthase and soluble guanylyl cyclase, thereby reducing pathologic vasodilation (similar to vasoplegia treatment post-cardiopulmonary bypass)
• Currently mentioned in one Spanish guideline; supported by animal models and case reports but not universally recommended
• Consider case-by-case when other second-line vasopressors fail

Extracorporeal Life Support (ECLS/VA-ECMO)

• Indicated for refractory cardiogenic shock from anaphylaxis or cardiac arrest not responding to all pharmacologic measures
• Listed in Miller's Anesthesia (10e) as an indication for VA-ECMO
• Requires specialist centre availability; bridge therapy while mediators clear

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Step 9: Airway Re-evaluation Before Extubation

• Persistent facial edema suggests ongoing laryngeal edema
• Keep intubated until edema resolves
• Test for air leak after cuff deflation before extubation
• If airway edema suspected, perform direct laryngoscopy before extubation

---

Monitoring Requirements

• Continuous vital signs and pulse oximetry
• 12-lead ECG (epinephrine toxicity, arrhythmias)
• Arterial line for beat-to-beat BP in severe cases
• Echocardiography to assess cardiac function/hypovolemia in refractory shock
• Serum tryptase (at 1-2h and 24h) to confirm mast cell activation

---

Disposition

• All patients with refractory anaphylaxis requiring IV epinephrine or airway intervention: admit to ICU
• Observe minimum 12-24 hours for biphasic reaction risk
• On discharge: prescribe epinephrine autoinjector, antihistamine, and corticosteroids (3-5 days); arrange allergy follow-up

---

Risk Factors for Refractory Anaphylaxis

• Beta-blocker or ACE inhibitor use
• Concurrent mastocytosis or elevated baseline tryptase
• Hereditary alpha-tryptasemia
• Platelet activating factor-acetylhydrolase (PAF-AH) deficiency
• Intraoperative/perioperative setting (venom, muscle relaxants, latex)

---

Summary Algorithm

IM Epinephrine x2-3 doses + IV fluids (20-30 mL/kg crystalloid)
         ↓ Still hypotensive/in shock?
IV Epinephrine INFUSION (0.1-0.5 mcg/kg/min, titrate)
         ↓ Still refractory?
Add vasopressor: Norepinephrine OR Vasopressin (0.01 units/min)
         ↓ On beta-blockers?
Glucagon 1-2 mg IV bolus → infusion
         ↓ Refractory bronchospasm?
Neb salbutamol + ipratropium + IV Magnesium sulfate 2g
         ↓ All failing?
Methylene Blue 1-2 mg/kg IV
         ↓ Cardiac arrest / No response?
VA-ECMO (specialist centre)

---

• Tintinalli's Emergency Medicine, 9th ed., Ch. 14
• Barash Clinical Anesthesia, 9th ed., Ch. on Anaphylaxis
• Miller's Anesthesia, 10th ed., Box 81.2
• Pouessel G et al. "Management of Refractory Anaphylaxis: An Overview of Current Guidelines." Clin Exp Allergy 2024 (PMID 38866583)
• Pouessel G et al. "Refractory Anaphylaxis: A New Entity for Severe Anaphylaxis." J Allergy Clin Immunol Pract 2023 (PMID 37172716)

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Glucagon in Refractory Anaphylactic Shock

When to Use Glucagon

• The patient is on beta-blockers (especially non-selective ones, e.g., propranolol, carvedilol) AND
• Shock persists despite adequate doses of epinephrine (IM or IV infusion) + aggressive IV fluid resuscitation

---

Mechanism of Action

• Binds its own glucagon receptor on cardiomyocytes and smooth muscle
• Directly activates adenylyl cyclase, raising intracellular cyclic AMP (cAMP)
• Produces positive inotropy and chronotropy - completely independent of β-adrenergic receptors
• Also reverses bronchospasm via the same cAMP-mediated pathway

---

Dosing and Administration

Adults

Pediatric

---

Preparation

• Glucagon is supplied as a lyophilized powder - must be reconstituted with the provided diluent (or sterile water) before IV use
• Reconstitution: 1 mg glucagon powder + 1 mL diluent = 1 mg/mL solution
• For infusion: dilute in D5W or NS to desired concentration; do NOT use saline containing calcium (may cause precipitation)
• Administer via a dedicated IV line if possible

---

Practical Administration Steps

1. Confirm beta-blocker use in the patient's medication history (or suspect it if epinephrine response is unexpectedly poor)
2. Ensure epinephrine has been given at appropriate doses first - glucagon is adjunct, not a replacement for epinephrine
3. Reconstitute glucagon and administer the IV bolus over ~5 minutes (rapid IV push can worsen nausea/vomiting and cause hypotension transiently)
4. Position patient supine - glucagon can cause vomiting; protect the airway (aspiration risk in drowsy/obtunded patients)
5. If hypotension improves with the bolus, start the maintenance infusion immediately
6. Continue epinephrine infusion alongside glucagon - they are complementary
7. Monitor blood glucose, electrolytes (hypokalemia), and vital signs continuously

---

Side Effects to Monitor

---

Important Caveats

• Evidence base is limited - all evidence is from case reports and expert consensus; no RCTs exist
• Glucagon should only be used after appropriate epinephrine has been tried - some case reports show that inadequate epinephrine dosing preceded glucagon use, and hemodynamic improvement may have occurred with optimal epinephrine alone
• It is a temporizing measure - the definitive treatment remains epinephrine + IV fluids + vasopressors
• Resuscitation Council UK (2021) states: consider glucagon when symptoms remain refractory to epinephrine infusion and adequate fluid resuscitation in beta-blocker users
• Some guidelines also list vasopressin (5-40 IU IV) as an alternative to glucagon for beta-blocker-associated epinephrine resistance

---

Summary Decision Point

Patient on beta-blockers + shock persists after:
   - Epinephrine (IM x2-3 doses or IV infusion) AND
   - IV crystalloid 20-30 mL/kg
           ↓
GIVE GLUCAGON
   Adult:  1-2 mg IV bolus over 5 min → repeat q5 min → infusion 5-15 mcg/min
   Child:  20-30 mcg/kg IV bolus → infusion 5-15 mcg/min
           ↓
Monitor: glucose, K+, nausea/vomiting, airway
Continue epinephrine infusion alongside

---

• Tintinalli's Emergency Medicine, 9th ed., Table 14-4, p. 112
• Goldman-Cecil Medicine, International Ed., p. 106
• Resuscitation Council UK, Emergency Treatment of Anaphylaxis, 2021
• Murakami Y et al. "Successful treatment of severe adrenaline-resistant anaphylactic shock with glucagon in a patient taking a beta-blocker." JA Clin Rep 2021 (PMID 34907487)
• Pouessel G et al. "Management of Refractory Anaphylaxis: An Overview of Current Guidelines." Clin Exp Allergy 2024 (PMID 38866583)

---

Hereditary Hemorrhagic Telangiectasia (HHT) - Osler-Weber-Rendu Syndrome

---

What Is It?

• Structurally abnormal vascular walls throughout the body
• Formation of telangiectasias (small dilated vessels) and arteriovenous malformations (AVMs) in multiple organs
• Recurrent spontaneous bleeding from affected sites
• Frequency: approximately 1 in 5,000 in the general population

---

The Classic Clinical Triad (Curacao Criteria)

3 criteria = definite HHT; 2 criteria = possible/suspected; < 2 = unlikely

---

Temporal Sequence of Manifestations

Childhood      → Epistaxis begins (50% of patients by age 10)
Adolescence    → Skin telangiectasias appear (face, lips, ears, chest, oral mucosa)
4th-5th decade → GI bleeding from telangiectasias and AVMs peaks
                 Visceral AVM complications (pulmonary, hepatic, cerebral, renal)

---

Organ Involvement - Full Spectrum

---

Genetics

---

Pathophysiology in Brief

---

Key Complications to Watch For

• Iron-deficiency anemia - from chronic GI and nasal bleeding; may be severe
• Stroke / brain abscess - via right-to-left shunting through pulmonary AVMs (paradoxical emboli)
• High-output cardiac failure - from large AV shunts (hepatic or pulmonary)
• Pulmonary hypertension
• Colorectal cancer - specifically in SMAD4 mutation carriers

---

Diagnosis

• Clinical: Curacao criteria (3 of 4 = definite)
• Genetic testing: 5-gene HHT panel (ENG, ACVRL1, MADH4, RASA1, BMP9) - sensitivity ~87% when all 4 Curacao criteria are present
• Screening for visceral AVMs: Echocardiography with bubble study (pulmonary AVM), CT chest, MRI brain, liver Doppler ultrasound
• Serum tryptase and VEGF levels correlate with severity

---

Management Highlights

• Epistaxis: Humidification, laser ablation, topical tranexamic acid, bevacizumab, septal dermoplasty
• GI bleeding: Iron supplementation, endoscopic argon plasma coagulation of telangiectasias, tranexamic acid, bevacizumab
• Pulmonary AVMs: Transcatheter embolization (if feeding vessel ≥3 mm)
• Hepatic AVMs: Liver transplantation for end-stage disease
• Cerebral AVMs: Neurosurgical or stereotactic radiosurgery consultation
• Renal AVMs/fistulas: Embolization or surgical management
• All patients: Carry medical alert; avoid anticoagulants where possible; family screening for first-degree relatives

---

• Sleisenger & Fordtran's Gastrointestinal and Liver Disease, p. 2299-2303
• Quick Compendium of Clinical Pathology, 5th ed., §7.3.4.2
• Grainger & Allison's Diagnostic Radiology, p. 711
• Cummings Otolaryngology, Head and Neck Surgery
• UpToDate: Clinical manifestations of HHT (updated March 2026)

---

Intravenous Iron Therapy - Dosing Guide

Step 1: Calculate Total Iron Deficit (Ganzoni Formula)

= 70 × (15 - 8) × 2.4 + 500 = 70 × 7 × 2.4 + 500 = 1,676 mg (round to nearest 100 mg = 1,700 mg)

Practical note: Ganzoni's formula tends to underestimate true requirements. Goldman-Cecil Medicine recommends the pragmatic approach of a flat 1,000 mg replacement dose for most adults, then recheck ferritin at 2-4 weeks and re-dose if ferritin remains <50 ng/mL. (Goldman-Cecil Medicine)

---

Simplified Dosing Table (for Ferric Carboxymaltose, ≥35 kg)

---

Step 2: Choose the IV Iron Preparation

---

Step 3: Administration Details

Iron Sucrose (most commonly used in CKD/HD)

• HD patients: 100 mg per dialysis session × 10 sessions = total 1,000 mg
• Non-HD/NDD-CKD: 200 mg per session, every other day until total dose reached; max 600 mg/week
• Dilute in 100-200 mL NS; infuse over 15-30 min
• Do NOT exceed 300 mg per session (risk of free iron generation)

Ferric Carboxymaltose

• ≥50 kg: 750 mg per infusion × 2 doses, ≥7 days apart (total 1,500 mg); or single 1,000 mg dose
• <50 kg: 15 mg/kg per infusion × 2 doses
• Infuse in 250 mL NS over ≥15 minutes; or undiluted slow IV push at 100 mg/min
• Max 15 mg/kg or 1,000 mg per single infusion
• Monitor serum phosphate - 75% of patients develop hypophosphatemia (<2.0 mg/dL)

Iron Dextran (Low MW)

• MUST give test dose: 25 mg IV over 5 min; wait 30-60 minutes; observe for reaction
• Full dose: dilute total replacement dose (up to 1,000 mg) in 250-500 mL NS; infuse over 1-4 hours
• Hold infusion pump available; keep epinephrine ready

Ferumoxytol

• 510 mg IV over ≥15 minutes; repeat in 3-8 days if TSAT <20%
• Warn patient and any future radiologists - acts as MRI contrast agent for months

---

Special Populations

---

Monitoring After IV Iron

---

Managing Infusion Reactions

Note: These are complement activation-related pseudoallergy (CARPA) reactions, not true IgE-mediated allergy. A test dose is therefore not helpful for non-dextran preparations - only iron dextran requires a test dose. (Goldman-Cecil Medicine)

---

When to Use IV Over Oral Iron

• No/poor response to oral iron after 2 weeks
• Intolerance to oral iron (GI side effects)
• Ongoing GI blood loss too great for oral iron to compensate
• Malabsorption: bowel resection, IBD, celiac disease, H. pylori, post-bariatric surgery
• Pregnancy (IV superior to oral)
• CKD on ESAs (functional iron deficiency)
• Heart failure with iron deficiency

---

• Goldman-Cecil Medicine, International Ed., p. 3116-3128
• Brenner & Rector's The Kidney, 2-Vol Set, p. 2483
• Goodman & Gilman's Pharmacological Basis of Therapeutics, Table 45-6
• NKF Primer on Kidney Diseases, 8th ed., p. 2094-2112
• Ferric Carboxymaltose (Ferinject) Datasheet, July 2024

---

Iron Sucrose (Venofer) Administration Plan for 796 mg Deficit

Your Dosing Plan at a Glance

Max 600 mg/week; alternate-day dosing keeps you within this limit safely. You can also give 3 sessions/week (Mon-Wed-Fri) as long as you don't exceed 600 mg that week.

---

Step-by-Step Administration for Each 200 mg Session

1. What You Need

• Iron sucrose (Venofer) 10 mL vial = 200 mg elemental iron (concentration: 20 mg/mL)
• 200 mL bag of 0.9% Sodium Chloride (Normal Saline)
• IV line, infusion pump
• Resuscitation equipment available (epinephrine, antihistamine, corticosteroids)

2. Preparation

• Draw up 10 mL of Venofer (= 200 mg)
• Add to 200 mL NS bag → total volume = 210 mL
• Mix gently - do NOT shake
• Use immediately after dilution (stable for 12 hours at room temperature but best used fresh)
• Do NOT dilute to lower concentrations than 1 mg/mL (stability issue)
• Do NOT mix with other IV medications or solutions other than NS

3. Infusion Rate

Alternatively: slow IV push undiluted at 1 mL/min (= 10 min for 200 mg / 10 mL) - but infusion is preferred and better tolerated.

4. No Test Dose Required

5. During Infusion

• Monitor vital signs at baseline, 15 min, and end of infusion
• Watch for: flushing, hypotension, chest/back pain, urticaria, nausea
• Have IV access patent throughout

6. Post-Infusion Observation

• Observe patient for at least 30 minutes after completion
• Confirm patient is haemodynamically stable before discharge

---

Managing Reactions (if they occur)

---

After All 4 Sessions: Follow-Up

Note: Ferritin stays elevated for 8-12 weeks post-infusion due to acute-phase response - do not recheck earlier than 4 weeks or you may falsely overestimate iron stores.

---

Summary Card for Nursing Staff

IRON SUCROSE (VENOFER) 200 mg per session × 4 sessions

Preparation:   10 mL Venofer + 200 mL 0.9% NaCl
Rate:          Infuse over 30 minutes
Frequency:     Alternate days (e.g. Mon / Wed / Fri / Mon)
Test dose:     NOT required
Observe:       30 min post-infusion
Total target:  800 mg (4 sessions)
Follow-up:     Ferritin + TSAT at 2-4 weeks after completion

---

• Venofer (Iron Sucrose) SmPC - Medicines.org.uk / FDA label
• Washington Manual of Medical Therapeutics, IV Iron Preparations table
• Goldman-Cecil Medicine, p. 3116-3122
• Brenner & Rector's The Kidney, 2-Vol Set, p. 2483

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Parkinsonism in an 81-Year-Old - First-Line Medications

Important Clinical Note First: Tremor Type

---

First-Line Drug: Levodopa/Carbidopa (Sinemet)

Why Levodopa Over Dopamine Agonists in This Patient?

"LD should be used when more potent therapy is indicated or in patients with late-onset disease" - Bradley & Daroff's Neurology in Clinical Practice

"Carbidopa/levodopa is the first-line choice for initial therapy in adults older than 65 years" - AAFP Guidelines

---

Starting Dose and Titration

Levodopa/Carbidopa (Sinemet) - Standard Tablet

Key Timing Rules

• Take 30-60 minutes BEFORE meals (protein competition reduces absorption - amino acids compete with levodopa at intestinal transport)
• Space doses every 4-6 hours for motor stability
• Do NOT stop abruptly - risk of neuroleptic malignant syndrome-like syndrome

Formulation Options

---

Second-Line Additions (Adjuncts in Elderly)

---

Drugs to AVOID in This 81-Year-Old

---

Monitoring After Starting

---

Essential Tremor vs. Parkinson Tremor - If Diagnosis Unclear

---

Summary for This Patient

Age 81 + Parkinsonism features:
   ↓
LEVODOPA/CARBIDOPA (Sinemet) 25/100 mg
   Start: ½ tablet 3× daily (30 min before meals)
   Titrate: increase by ½ tab every 3-7 days
   Target: 1 tablet (100 mg levodopa) 3× daily
   ↓
If tremor persists AND features suggest Essential Tremor:
   Add low-dose Propranolol 20 mg BD (if BP/cardio permits)
   ↓
AVOID: Dopamine agonists, anticholinergics, typical antipsychotics

---

• Bradley & Daroff's Neurology in Clinical Practice, 8th ed., Ch. 96 (Treatment of Parkinson Disease)
• AAFP: Parkinson Disease, Am Fam Physician 2020;102(11):679-691
• Dtsch Arztebl Int 2025: Treatment of Older Patients with Parkinson's Disease
• PMC3024520: Seniors with Parkinson's Disease: Initial Medical Treatment

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Albumin Regimen for Hepatorenal Syndrome (HRS)

Understanding the Role of Albumin in HRS

• Expanding effective circulating volume
• Maintaining/increasing cardiac output (even in advanced liver disease)
• Binding inflammatory mediators and endotoxins
• Potentiating the hemodynamic effects of vasoconstrictors

---

Standard Albumin Regimen for HRS-AKI (Type 1 HRS)

Phase 1 - Diagnostic/Volume Challenge (Days 1-2)

If AKI reverses after 2 days → diagnosis was prerenal azotemia, NOT HRS If AKI persists → confirmed HRS-AKI; continue to treatment phase

---

Phase 2 - Treatment Phase (Day 3 onward, up to 14 days)

---

Albumin Concentration to Use

For 1 g/kg × 70 kg = 70 g: give 350 mL of 20% albumin or 280 mL of 25% albumin

---

Combined Vasoconstrictor Regimen (Albumin Must be Given WITH These)

Option 1: Terlipressin + Albumin (First-Line - where available)

FDA-approved Terlivaz (terlipressin) dosing (USA): 1 mg IV every 6 hours; escalate to 2 mg IV every 6 hours on Day 4 if SCr decrease <30% from baseline HRS reversal rates: 34-83% with terlipressin + albumin vs. 0-19% with albumin alone

Option 2: Norepinephrine + Albumin (ICU Setting, where terlipressin unavailable)

Norepinephrine requires ICU/HDU monitoring; comparable efficacy to terlipressin in some trials

Option 3: Midodrine + Octreotide + Albumin (Outpatient/Ward Setting, where terlipressin unavailable)

Less effective than terlipressin; reversal ~40%; used when other vasoconstrictors not available

---

Response Assessment

---

HRS Reversal Definition

• Complete reversal: SCr decreases to <1.5 mg/dL (or to within 0.3 mg/dL of baseline)
• Partial response: SCr decreases ≥50% but does not reach target
• No response: <30% decrease in SCr after dose escalation

---

Special Context: Albumin in SBP-associated HRS Prevention

Indicated when: BUN >30 mg/dL, creatinine >1 mg/dL, OR bilirubin >4 mg/dL Max 100 g per dose; reduces risk of renal failure and acute mortality

---

Special Context: Albumin in Large Volume Paracentesis (LVP) - Prevention

---

Monitoring During Albumin + Vasoconstrictor Therapy

---

Contraindications to Terlipressin (switch to norepinephrine)

• Severe respiratory failure / ARDS (risk of worsening hypoxia)
• Known ischaemic heart disease / peripheral vascular disease
• Active ischaemia anywhere
• Uncontrolled sepsis

---

Definitive Treatment: Liver Transplantation

---

Summary Dosing Card

HRS-AKI ALBUMIN REGIMEN

STEP 1 - Volume Challenge (Rule out prerenal):
  Albumin 1 g/kg IV (max 100g) on Day 1 AND Day 2

STEP 2 - Confirmed HRS: Start Vasoconstrictor + Albumin
  Terlipressin:  0.5-1 mg IV q4-6h → escalate to 2 mg q4-6h if SCr ↓<30% by Day 3-4
  PLUS
  Albumin:       20-40 g IV once daily (20% or 25% solution)

STEP 3 - Duration: Up to 14 days
  Stop if: SCr <1.5 mg/dL (success) OR no response by Day 14

SBP-ASSOCIATED HRS PREVENTION:
  Albumin 1.5 g/kg IV at diagnosis + 1 g/kg IV on Day 3

---

• Goldman-Cecil Medicine, International Ed., Hepatorenal Syndrome section
• Current Surgical Therapy, 14th ed. - Vasoconstrictors and Albumin
• Comprehensive Clinical Nephrology, 7th ed., Table 76.2 (RCT data)
• Gastroenterology 2024 - "Hepatorenal Syndrome in Cirrhosis" (EASL/AASLD guideline comparison)
• e-CMH 2023 - "Hepatorenal Syndrome" - dosing review
• CONFIRM Trial (terlipressin + albumin vs. placebo + albumin)

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IgG4-Related Pancreatitis (Type 1 Autoimmune Pancreatitis)

What Is It?

---

Type 1 vs. Type 2 AIP - Key Differences

---

Clinical Presentation

Symptoms

• Painless obstructive jaundice - most common presentation (mimics pancreatic cancer / cholangiocarcinoma)
• Abdominal or back pain (less typical than in acute pancreatitis)
• Weight loss
• New-onset diabetes mellitus (exocrine and endocrine insufficiency)
• Rarely: acute pancreatitis presentation
• Symptoms from other organ involvement (see below)

Demographics

• Typically presents in patients >60 years old, male
• Often diagnosed incidentally or when investigating a pancreatic "mass"

---

Organ Involvement in IgG4-RD (Extrapancreatic)

---

Imaging Findings

CT / MRI - Classic Appearance

Key differentiator from pancreatic cancer: AIP causes ductal stricture WITHOUT upstream duct dilation; cancer typically causes obstruction WITH marked upstream dilation

---

Diagnosis - International Consensus Diagnostic Criteria (ICDC)

Definitive Type 1 AIP Diagnosis Requires (ICDC):

1. Periductal lymphoplasmacytic infiltrate (without granulocytes)
2. Obliterative phlebitis
3. Storiform fibrosis
4. IgG4-positive cells >10 per high-power field

1. Elevated serum IgG4
2. ≥2 classic histology findings
3. Other organ involvement (histologic or radiographic)
4. Response to corticosteroids

---

Serum IgG4 - Interpretation

Important caveat: Pancreatic cancer can also raise IgG4, but <1% of pancreatic cancer patients have levels >2× ULN. Always correlate with imaging and clinical context.

---

Histopathology - 4 Key Features of Type 1 AIP

---

Treatment

Indications for Treatment

• Symptomatic disease (jaundice, pain, weight loss)
• Persistent pancreatic mass on imaging
• Persistent abnormal liver tests from IgG4-sclerosing cholangitis
• Exocrine/endocrine insufficiency
• Other organ involvement threatening irreversible damage

10-25% of patients may have spontaneous remission without treatment

First-Line: Corticosteroids

Remission induction rate with steroids: up to 99% Low-dose maintenance therapy reduces relapse rate significantly (Japanese multicenter study of 510 patients)

Response Assessment

• Symptom improvement: within 1-2 weeks
• Imaging improvement: within 2-4 weeks (sausage pancreas resolves)
• If NO response at 4-6 weeks → MUST exclude pancreatic cancer
• A diagnostic steroid trial can be given when histology is unavailable and diagnosis is probable

Relapse Management

• Relapse in 30-50% of Type 1 AIP (much higher than Type 2)
• Repeat steroid induction course
• Consider adding a steroid-sparing immunomodulator

Second-Line / Steroid-Sparing Agents

---

Complications if Untreated

• Chronic pain
• Exocrine pancreatic insufficiency (steatorrhea, malabsorption)
• Endocrine insufficiency (diabetes mellitus)
• Pancreatic fibrosis / atrophy
• IgG4-sclerosing cholangitis → biliary stricture → secondary biliary cirrhosis
• Unnecessary pancreatic surgery

---

Long-Term Follow-Up

---

Key "Do Not Miss" Points

---

• Current Surgical Therapy, 14th ed., Ch. - Autoimmune Pancreatitis (Tables 1, 2, 3; Figs 1, 2)
• Goldman-Cecil Medicine, International Ed.
• UpToDate: Autoimmune Pancreatitis - Clinical Manifestations and Diagnosis (updated 2026)
• NCBI StatPearls: Autoimmune Pancreatitis
• Wu S et al. "A comprehensive review of IgG4-related pancreatitis." Front Immunol 2025 (PMID 40599784)
• Clin Am 2025: What Is the Latest in Autoimmune Pancreatitis

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Enterococcus faecalis UTI - Treatment Duration & Antibiotic Guide

Important Stewardship Point First

E. faecalis is part of normal rectal flora and is frequently a contaminant in urine specimens, especially catheter samples. Treat only when there are genuine urinary symptoms + pyuria + significant colony counts (≥10³ CFU/mL in catheter, ≥10⁵ in midstream). (IDSA/Stanford Stewardship, 2024)

---

Treatment Duration by Clinical Category

IDSA 2025 key update: Shorter courses (5-7 days for fluoroquinolone; 7 days for beta-lactam) are now preferred over traditional 10-14 days for complicated UTI/pyelonephritis in patients improving clinically on effective therapy. Longer courses (10-14 days) may still be needed for indwelling catheters, severe sepsis, immunocompromise, abscess, obstruction, or CKD.

---

Antibiotic Choice for E. faecalis UTI

First-Line Agents

Second-Line / Alternative Agents

For Vancomycin-Resistant Enterococcus (VRE) - E. faecium more common, but E. faecalis VRE exists

What Does NOT Work for E. faecalis

---

Special Situations

Pregnant Women

• Amoxicillin 500 mg TID × 7 days (cystitis)
• Nitrofurantoin safe in 1st/2nd trimester but avoid near term (neonatal hemolytic anemia risk)
• Treat all bacteriuria in pregnancy, even if asymptomatic

Catheter-Associated UTI

• Remove or replace the catheter before or at the start of antibiotic therapy - this alone can resolve bacteriuria
• 7 days if prompt clinical improvement after catheter management
• 10-14 days if delayed response

Recurrent E. faecalis UTI

• Check for underlying structural cause (stones, incomplete voiding, BPH in males)
• Consider long-term prophylaxis only after urological workup
• Nitrofurantoin 50-100 mg nocte for continuous prophylaxis (lower UTI prevention)

---

Summary Decision Table

E. faecalis UTI confirmed (symptomatic + pyuria)
            ↓
UNCOMPLICATED CYSTITIS (female, no complicating factors):
   → Amoxicillin 500 mg TID × 5-7 days
   → OR Nitrofurantoin 100 mg BD × 5-7 days

COMPLICATED UTI / PYELONEPHRITIS (improving on therapy):
   → Amoxicillin 500 mg TID × 7 days (oral)
   → OR Ampicillin 1g IV q6h then step down to oral × 7 days total

CAUTI:
   → Remove/replace catheter + Amoxicillin × 7 days
   (extend to 10-14 days if slow improvement)

MALE / PROSTATITIS:
   → Amoxicillin × 14 days (acute)
   → Consult urology if refractory

VRE cystitis:
   → Fosfomycin 3g single dose OR Linezolid 600 mg BD × 5-7 days (consult ID)

---

• Comprehensive Clinical Nephrology, 7th ed., Ch. 53 (UTI definition, epidemiology, etiologic agents)
• Medical Microbiology, 9th ed. (Enterococcus treatment - penicillin/ampicillin first-line)
• Harrison's Principles of Internal Medicine, 22nd ed. (2025) - Enterococcal infections
• IDSA 2025 Guideline Update: Complicated UTI treatment duration (idsociety.org)
• Stanford Antimicrobial Safety Program: Enterococcus/VRE in Urine Cultures, 2024

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Vancomycin Therapeutic Drug Monitoring - When & How

The Paradigm Shift: Trough vs. AUC (2020 Guidelines)

Trough-only monitoring is still used in many institutions where Bayesian software is unavailable, particularly for non-MRSA indications.

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When to Draw the Trough Level

Standard Intermittent Dosing (Most Common)

In infants (faster elimination, shorter t½): draw trough before the 3rd dose

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Timing Summary by Dosing Interval

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For AUC-Guided Monitoring (2020 Preferred Method)

Both samples ideally collected at steady state (around 3rd-4th dose) Target: AUC₂₄ = 400-600 mg·h/L (assuming MIC = 1 mg/L by broth microdilution) These AUC targets should be achieved within 24-48 hours of starting therapy

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Target Levels - Trough-Based (When AUC Not Available)

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Repeat / Ongoing Monitoring: When to Recheck

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Special Situations

When to Draw an EARLY (Non-Steady State) Level

• If concerned about toxicity (rising creatinine, oliguria) before steady state
• If suspected supratherapeutic initial level (e.g., overdose, accidental double dose)
• Patients with rapidly changing renal function (AKI)
• Draw at ~2h post-infusion (peak); use Bayesian software to calculate estimated AUC even before steady state

When to Draw a PEAK Level Specifically

• Suspected CNS infections (target peak ≥30 mg/L)
• Burns patients (altered Vd and clearance)
• Clinical non-response at 72h despite adequate troughs
• Persistent positive cultures despite therapy

Loading Dose Timing

• If a loading dose is given (25-30 mg/kg, max 3,000 mg):
  • This rapidly achieves near-therapeutic levels
  • AUC targets can be achieved within 24-48h when loading + Bayesian approach used
  • Draw 2 levels 1-2h post-loading infusion end and just before next dose for Bayesian calculation

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High-Risk Patients Requiring More Vigilant Monitoring

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Practical Step-by-Step Guide

STEP 1 - Start vancomycin
   Loading dose: 25-30 mg/kg IV (max 3,000 mg) for serious infections
   Maintenance: based on CrCl and weight

STEP 2 - Draw levels at steady state (3rd-4th dose)
   AUC method (preferred):
     → Draw peak 1-2h post-infusion end AND trough <30 min pre-dose
     → Enter into Bayesian software → calculate AUC₂₄
     → Target: 400-600 mg·h/L

   Trough-only method (if AUC not available):
     → Draw trough within 30 min BEFORE 4th dose
     → Target: 10-14 mg/L (mild) or 14-17 mg/L (serious)

STEP 3 - Adjust dose based on result
   → Recheck after 4th dose of NEW regimen

STEP 4 - Ongoing monitoring
   → Stable patient: every 5-7 days
   → Changing renal function: every 1-2 days
   → Hemodialysis: pre- and post-each dialysis session

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Why NOT Trough Alone Anymore

• Trough 15-20 mg/L is a poor surrogate for AUC - a wide variety of AUC values can produce the same trough depending on the dosing interval
• Troughs ≥15 mg/L are independently associated with AKI without reliably achieving the AUC/MIC target needed for efficacy
• AUC/MIC-guided dosing achieves equivalent clinical outcomes with significantly less nephrotoxicity

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• Harriet Lane Handbook, 23rd ed. (Johns Hopkins), Vancomycin section (p. 1389-1390)
• ASHP/IDSA/PIDS/SIDP 2020 Consensus Guidelines: Therapeutic Monitoring of Vancomycin
• ASHP Guideline on Vancomycin Monitoring (Am J Health-Syst Pharm 2020)